Extremely high-frequency electronic device



Oct. 5, 1954 w. w. sALlsBuRY EXTREMELY HIGH-FREQUENCY ELECTRONIC DEVICES`Filed Jan. 23, 1950 www@ Patented Oct. 5, 1954 mur; sAres ATENT OFFICEEXTREMELY HIGH-FREQUENCY ELECTRONIC DEVICE Application January 23, 1950,Serial No. 140,103

1 Claim.

This invention relates in general to extremely high frequency electronicdevices as, for example, between 25pm-590,000 mc.

It is an object of this invention to provide a device for modulating andamplifying a beam of electrons passing through a wave guide.

A further object of this invention is to provide a device in theextremely high frequency range for mixing a plurality of signals Afeature of this invention is found in the provision for an electron beamproducing means which supplies a beam of electrons to a tunable waveguide section into which is coupled an extremely high frequency signal.A tunable receiving wave guide section is mounted in axial alignmentwith the transmitting wave guide section and an energy coupling means isconnected thereto for removing energy at a high power level.

Another feature of this invention is the provision for a plurality ofwave guide sections spaced in axial alignment with an energy couplingloop connected to each section and energy removing means withdrawing amixed signal from a collector electrode.

Further objects, features, and advantages will become apparent from thefollowing specifications and drawings; in which Figure 1 is aperspective View of the apparatus of this invention illustrating how itmay be used as an amplifier; and

Figure 2 is a perspective view of the apparatus of this inventionillustrating how it may be used as a mixing device.

Referring to Figure l, a Wave guide section it contains therein aslidable shorting member Il. An opening l2 is formed in the member Iland an electron gun i3, of a kind well known to those skilled in theart, produces a 'beam of electrons and shoots it through the opening l2and axially through the Wave guide section It. The slidable member i lmay be adjusted axially of the wave guide by tuning means including theplungers lll and i5 which are received in a bracket il. A coupling loopi8 extends downwardly into the wave guide section ahead of the slidablemember and furnishes extremely high frequency modulation energy to thewave guide. The slidable member Il is moved axially of the wave guideuntil it is tuned to the input frequency from the coupling loop IB. Whentuning has occurred, there will be an energy transfer between the inputsupplied to the coupling loop and the beam of electrons passing axiallydown the wave guide.

The wave guide ill terminates in a grid i9 which may comprise, forexample, a wire screen. The electron beam passes through the grid into adrift space between the wave guide lil and a second wave guide 2! Theopen end of the second Wave guide is closed by means of a second grid 2uand the beam passes therethrough. Adjacent the opposite end of the waveguide 2l is a slidable tuning bar 22 which may be moved axially of thewave guide section. An energy coupling loop 23 extends downwardly intothe confines of the wave guide section 2l to remove energy therefrom.The tuning bar 22 may be adjusted so that the receiving Wave guide 2| istuned to the sending wave guide l0.

As the electron beams pass through the drift space bunching of theelectrons occurs and the bunched electrons couple energy to the outputloop 23 as they pass thereby. The electron beam impinges on the snortingbar 22 and is removed from the apparatus. A plunger l0 is attached tosnorting bar 22.

In order for the wave guide energy transfer device above described tooperate, the gain due to the electrons between the input and outputloops must be greater than the one-way transmission loss between them.In other words, the feed-back from the output coupling loop 23 must notbe so great that the incoming signal fed to the coupling loop i8 iscancelled or reinforced. This condition exists When the Wave guides areseparated.

If the proper material is used in constructing the wave guide, only oneway guide section need be used instead of the two above described. Inthis case the input coupling loop and the output coupling loop may bothbe placed within the same Wave guide section and the grids I9 and 2Ddeleted. The transmission loss of the material from which the wave guideis made must be such that the transmission attenuation of the signal ismore than the gain of the tube which is equal to the electron gain plusthe transmission loss if loss is positive.

The gain of the tube is equal to the electron gain minus thetransmission loss. For example, an iron wave guide may have a highenough resistance for this purpose.

(l) The tube gain is equal to the electron gain minus the transmissionloss;

(2) The electron gain must be greater than the transmission loss; andtherefore (3) The electron gain is greater than the tube gain.

The above three statements express the necessary conditions foramplification to occur in the tube. n

Figure 2 illustrates apparatus which may be used for mixing a. pluralityof extremely high frequency signals. A wave guide section 26 has anelectron gun 21' slidably mounted therein in a manner similar to thatshown in Figure 1. The Wave guide 26 terminates in a screen 28 and aninput coupling loop 29 furnishes an extremely high frequency input formodulating the beam of electrons from the gun 21. The wave guide section26 is tuned to the same frequency as the input fed to the loop 29.

Another wave guide section 3l is maintained in axial alignment with therst section 2E and the ends are covered by screens 32 and 33. An inputloop 34 feeds a signal into the waveguide 3l which modulates theelectron beam passing therethrough. The beam has previously beenmodulated by the input fed to loop 29 and thus often it passes throughthe wave guide 3l contains the mixed signals from the inputs 29 and 34.

A collector electrode 35 received the electron beam. As illustrated, thedifference frequency (f1-fz) may be chosen by connecting the electrode36 to a circuit 31 timed to the difference frequency. One end of circuit3l is connected to an external terminal 4I. A grounded terminal 42 ismounted adjacent terminal 4|. The sum of the mixed frequencies (f1-H2)may be obtained by replacing the collector electrode by a Wave guidesection tuned to the sum frequency. An output loop may remove the energyfrom the wave guide section.

It is seen that more than two signals may be combined by installing aplurality of Wave guide sections in axial alignment and supplying aninput to each one. The electron beam may be maintained in focusmagnetically or in any other well-known manner.

The plurality of wave guide sections may be replaced by a single waveguide if the three conditions for preventing ring are maintained. Thisrequires that a relative high resistant material be used in the waveguide. The signals to be mixed are fed into the wave guide by means ofcoupling loops longitudinally spaced along the tube. It is to berealized that the structure of this invention is enclosed in a suitableenvelope 38 which supports the various elements by standoffs 39. Thespace within the envelope may be evacuated.

It is seen that this invention provides a mixer and ampliiier in theextremely high frequency range and thus makes it possible to use thesefrequencies in manners that have heretofore been considered impossible.

Although this invention has been described with respect to particularembodiments thereof, it is not to be so limited as changes andmodications may be made therein which are within the full intended Scopeas defined by the appended claim.

I claim:

An extremely high frequency amplifier comprising a iirst rectangularwave guide section with a siidable shorting bar mounted therein forlongitudinal movement, an electron gun for shooting a beam of electronsthrough an opening formed in said shorting bar and longitudinally ofsaid wave guide, a second rectangular Wave guide section in axialalignment with said first Wave guide section for receiving the beam ofelectrons therein, a collector electrode slidably mounted forlongitudinal movement in said second wave guide section, an input loopfor coupling energy into said rst wave guide section, and an output loopfor coupling energy from said second wave guide section.

References Cited in the ille of this patent UNITED STATES PATENTS NumberName Date 2,190,515 Hahn Feb. 13, 1940 2,220,839 Hahn Nov. 5, 19402,309,966 Litton Feb. 2, 1943 2,367,295 Llewellyn Jan. 16, 19452,414,843 Varian Jan. 28, 1947 2,436,997 Morton Feb. 24, 1948 2,450,026Tomlin Sept. 28, 1948 2,452,566 Hansen Nov. 2, 1948 2,484,643 PetersonOct. 11, 1949

